From a4c4af7c8dc1eccdfb8c57e1684f08179b4407e6 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 7 Nov 2005 00:58:38 -0800 Subject: [PATCH] [PATCH] cpu hoptlug: avoid usage of smp_processor_id() in preemptible code Replace smp_processor_id() with any_online_cpu(cpu_online_map) in order to avoid lots of "BUG: using smp_processor_id() in preemptible [00000001] code:..." messages in case taking a cpu online fails. All the traces start at the last notifier_call_chain(...) in kernel/cpu.c. Since we hold the cpu_control semaphore it shouldn't be any problem to access cpu_online_map. The reason why cpu_up failed is simply that the cpu that was supposed to be taken online wasn't even there. That is because on s390 we never know when a new cpu comes and therefore cpu_possible_map consists of only ones and doesn't reflect reality. Signed-off-by: Heiko Carstens Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched.c | 3 ++- kernel/softirq.c | 3 ++- kernel/softlockup.c | 3 ++- kernel/workqueue.c | 2 +- 4 files changed, 7 insertions(+), 4 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index b4f4eb613537..013f1448006b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4680,7 +4680,8 @@ static int migration_call(struct notifier_block *nfb, unsigned long action, #ifdef CONFIG_HOTPLUG_CPU case CPU_UP_CANCELED: /* Unbind it from offline cpu so it can run. Fall thru. */ - kthread_bind(cpu_rq(cpu)->migration_thread,smp_processor_id()); + kthread_bind(cpu_rq(cpu)->migration_thread, + any_online_cpu(cpu_online_map)); kthread_stop(cpu_rq(cpu)->migration_thread); cpu_rq(cpu)->migration_thread = NULL; break; diff --git a/kernel/softirq.c b/kernel/softirq.c index f766b2fc48be..ad3295cdded5 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -470,7 +470,8 @@ static int __devinit cpu_callback(struct notifier_block *nfb, #ifdef CONFIG_HOTPLUG_CPU case CPU_UP_CANCELED: /* Unbind so it can run. Fall thru. */ - kthread_bind(per_cpu(ksoftirqd, hotcpu), smp_processor_id()); + kthread_bind(per_cpu(ksoftirqd, hotcpu), + any_online_cpu(cpu_online_map)); case CPU_DEAD: p = per_cpu(ksoftirqd, hotcpu); per_cpu(ksoftirqd, hotcpu) = NULL; diff --git a/kernel/softlockup.c b/kernel/softlockup.c index 75976209cea7..a2dcceb9437d 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -123,7 +123,8 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) #ifdef CONFIG_HOTPLUG_CPU case CPU_UP_CANCELED: /* Unbind so it can run. Fall thru. */ - kthread_bind(per_cpu(watchdog_task, hotcpu), smp_processor_id()); + kthread_bind(per_cpu(watchdog_task, hotcpu), + any_online_cpu(cpu_online_map)); case CPU_DEAD: p = per_cpu(watchdog_task, hotcpu); per_cpu(watchdog_task, hotcpu) = NULL; diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 7cee222231bc..42df83d7fad2 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -524,7 +524,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, list_for_each_entry(wq, &workqueues, list) { /* Unbind so it can run. */ kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, - smp_processor_id()); + any_online_cpu(cpu_online_map)); cleanup_workqueue_thread(wq, hotcpu); } break; -- 2.25.1